Formation of nanoperiodic structures based on keggin and lacunar anions of phosphotungstic acid and cationic surfactants

Surface-active cations (A⁺) in an aqueous medium, at pH 1.0 with excess phosphotungstic acid, form compounds with the composition A₃[PW₁₂O₄₀]; but at pH 4.5, they form acid salts A_nH_7−n[PW₁₁O₃₉]·xH₂O that have a nanoperiodic structure. The structural parameters are greatly dependent on the nature of the surfactant and on the type of heteropolyion. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospect Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 4, pp. 250–256, July–August, 1998.